Recital (28)

To design the sampling survey for soil monitoring, Member States will need to take into account their soil districts and soil units. In order to ensure a sufficient level of harmonisation between Member States, a set of minimum criteria for defining soil units should be established at Union level, taking into account at least the soil type and land use. For that purpose, the map of the Soil Regions of the European Union and Adjacent Countries 1:5000000, published by the Federal Institute of Geosciences and Natural Resources (BGR), in partnership with the Joint Research Centre (JRC), could be used. That map builds on soil types as defined in the World Reference Base for Soil Resources, coordinated by the International Union of Soil Sciences, as well as on fully comparable and harmonised basic data at the continental level, such as on climate, topography, relief, geology and vegetation. As regards land use, the categories defined in Regulation (EU) 2018/841 and the Intergovernmental Panel on Climate Change (IPCC) Guidelines serve as a harmonised basis for land use reporting. Therefore, in order to delineate soil units, Member States should take into account at least the soil districts, as well as the soil regions and the land use categories. On account of spatial variability in soil properties and land use, a soil unit can consist of non-adjacent areas. In addition, climatic and environmental conditions can be taken into account when delineating soil units. More detailed or updated information at the Union, national or subnational level could be used, where available. When establishing their soil units, Member States can draw on additional available data on climate, environmental zones or river basins. In this context, the Alterra Report 2281 on Descriptions of the European Environmental Zones and Strata of January 2012 is especially relevant as it provides datasets on generic classification of environmental stratification of Europe, aggregated into environmental zones, which can be used for the establishment of soil units by Member States.